I wonder how many of those who have backed Tricky Trickster for the Grand National can remember the evacuation of Dunkirk. Very few, one imagines, and even fewer will realise that they have bet on something which has not happened since then.

Bogskar in 1940 was the last seven-year-old to win the famous Aintree race, but it is striking how many horses of that tender age feature among this year's entrants. Apart from Tricky Trickster, the 12-1 favourite, there is the 20-1 shot Possol, as well as contenders like The Package, Le Beau Bai, Deutschland, Piraya and Palypso De Creek.

On recent form, these horses are most unlikely to complete the course. A total of 21 seven-year-olds have lined up since 1999 and 15 of them have either fallen or unseated. They include Eudipe in 1999 and Jurancon in 2004, both well-fancied 10-1 shots, while Iris Bleu, the 8-1 second-favourite in 2003, was pulled up on the first circuit after three significant errors.

The Grand National is certainly changing, but not in favour of younger horses. The fences may be less formidable but the result is that the runners go faster, so that any mistake is as expensive as ever. For a horse with limited experience of jumping fences at speed, the modern National must be very intimidating.

Tricky Trickster has had a total of five runs over fences, four of them in races restricted to novices. He also has more weight to carry than any winner since 1983. If he is good enough to overcome all that and be the first of his age to succeed for 70 years, I will salute him, but he will not carry my money.

The Grand National has had its problems with bits of tape in the past but just a small amount of the stuff could have prevented controversy at Newcastle on Tuesday, when five horses, including the 6-4 favourite, took the wrong course and were disqualified. Just as with a similar incident involving Barry Geraghty at Wetherby in October, the problem was caused by an island of white rail between the chase course and the hurdles course; instead of going to the right of it, the errant riders went left.

As ever, there is no question about who bears primary responsibility for this. Jockeys are supposed to walk the course beforehand, study maps of it in the weighing room and generally get a pretty good idea of which way they should be facing.

Still, it would be nice to think that racing's administrators were keen to do everything possible to minimise the chance of something going wrong. At a time when racing is spending hundreds of thousands of pounds trying to broaden its appeal, it seems madness to antagonise existing devotees by allowing the continued risk of such idiotic calamities.

Happily, it seems that things are moving in the right direction. The British Horseracing Authority has worked to improve the layout at both Wetherby and Newcastle and intends to contact all courses about the issue.

"What we've learned is that we have to limit the potential for these things to happen," Newcastle's clerk of the course, James Armstrong, told me. Here's hoping all other courses put those sensible words into action.